Today, copying machines, facsimile machines, printing apparatuses, etc., are indispensable for paper work in offices. These copying machines, facsimile machines, printing apparatuses, etc., are each configured based on an image recording apparatus. Recently, an image recording apparatus is drawing attention as a multi-function peripheral incorporating all the functions of a copying machine, a facsimile machine, a printing apparatus, etc. The image recording apparatus includes as a basic function a function of recording an image such as characters and charts onto a recording medium such as recording paper in the form of a sheet. Recording of an image can be recording of a monochrome image and recording of a color image.
Recently, due to the increase of the amount of the paperwork, improvement of the processing speed of the image recording apparatus is demanded to the above image recording apparatus. Because an image recording apparatus is an apparatus that records an image, the improvement of the processing speed is, in other words, improvement of the speed of recording onto a recording paper sheet that is a recording medium and ejecting the paper sheet. Therefore, improvement of the number of sheets of recording paper that are recorded and ejected per unit time is demanded.
In response to such demand, in addition to a method of facilitating the improvement of the processing speed of the image recording apparatus itself, a method of improving the processing speed comprehensively by using a plurality of image recording apparatuses can be contemplated. To cope with the above demand in such a viewpoint, various proposals have been made (see, for example, Japanese Laid-Open Patent Publication Nos. H1-112275 and H8-305221).
Japanese Laid-Open Patent Publication No. H1-112275 describes an image forming apparatus that includes both of a color image forming apparatus and a monochrome electronic photograph apparatus.
Japanese Laid-Open Patent Publication No. H8-305221 describes a technique that facilitates the improvement of the processing speed by configuring a color printing apparatus using a plurality of color image forming apparatuses and adapting the color printing apparatus to configure the color image forming apparatuses to output continuously a large amount of prints and eject the prints at a high speed placing the prints in order of page number thereof on bins in a common sorter by controlling the printing process in each color image forming apparatus. The color printing apparatus described in Japanese Laid-Open Patent Publication No. H8-305221 operates two color image forming apparatuses simultaneously to improve the speed of the processing thereof.
Generally, an image recording apparatus is caused to process at one time one image recording job that executes a series of image recording processes, that is, one image recording job that executes image recording consecutively of images each of which is independent for each page onto a plurality of recording paper sheets in order of page number. In this regard, same procedure as above is also taken in the color printing apparatus described in Japanese Laid-Open Patent Publication No. H8-305221 that is configured using a plurality of color image forming apparatuses to facilitate the improvement of the processing speed thereof. That is, the color printing apparatus described in Japanese Laid-Open Patent Publication No. H8-305221 processes one image recording job at one time. The apparatus facilitates improvement of the processing speed thereof by processing in a distributed manner using a plurality of color image forming apparatuses. Therefore, the plurality of image forming apparatuses configuring such a color printing apparatus must be all the same type of apparatuses, that is, color image forming apparatuses.
However, for conventional image recording systems each configured by a plurality of image recording apparatuses in addition to those described in Japanese Laid-Open Patent Publication Nos. H1-112275 and H8-305221, time from setting an original document and pressing down an operational button (“copy” button or “start” button) to outputting of a sheet that is printed first as a recorded item into a containing portion (FCOT: First Copy Time) and the case where the image recording process can not be continued temporarily or until repairing is completed are not considered. Therefore, for a conventional image recording system, the processing speed is felt to be slow and discomfort is generated.
For example, the image forming apparatus described in Japanese Laid-Open Patent Publication No. H1-112275 includes the color image forming apparatus and the monochrome electronic photograph apparatus, and can record superimposing on a color image obtained by the color image forming apparatus using the monochrome electronic photograph apparatus and operate each of the included apparatuses independently. However, the image forming apparatus is an invention strictly for improving the image quality and can not switch the included apparatuses for each one image recording job. Therefore, the image forming apparatus described in Japanese Laid-Open Patent Publication No. H1-112275 can not execute control to improve FCOT, and substitute printing for the case where the image recording process can not be continued temporarily or until repairing is completed.
The color printing apparatus described in Japanese Laid-Open Patent Publication No. H8-305221 includes the same type of color image forming apparatuses as described above and only facilitates the improvement of the processing speed thereof by processing one image recording job in a distributed manner using the plurality of color image forming apparatuses. Therefore, the color printing apparatus can not facilitate improvement of FCOT and can not execute substitute printing for the case where the image recording process can not be continued temporarily or until repairing is completed.
A technique is also present that, in the case where an image recording process is requested from a personal computer (PC), etc., when the image recording system can not process the requested process, requests substitute processing to another image recording apparatus, etc., that is connected with a network. However, recorded items are distributed at scattered places and labor to retrieving the recorded items is generated.